Interactions of Aqueous Imidazolium-Based Ionic Liquid Mixtures with Solid-Supported Phospholipid Vesicles

Area of Science:

• Biophysics
• Materials Science
• Cell Biology

Background:

• Ionic liquids (ILs) are increasingly used but their cellular safety is questioned due to potential cytotoxicity.
• Understanding IL-cell interactions is crucial for assessing their biological impact and applications.
• Biomimetic membranes serve as valuable models to study these fundamental interactions.

Purpose of the Study:

• To investigate the effects of aqueous imidazolium-based ionic liquid mixtures on solid-supported biomimetic membranes.
• To elucidate the influence of IL cation chain length and anion type on membrane integrity and lipid behavior.
• To analyze the real-time interactions using dissipative quartz crystal microbalance with dissipation monitoring (QCM-D).

Main Methods:

• Utilized dissipative quartz crystal microbalance with dissipation monitoring (QCM-D) for real-time analysis.
• Employed solid-supported biomimetic membranes composed of the model phospholipid DMPC.
• Systematically varied ionic liquid composition, focusing on cation hydrophobicity and anion nature.

Main Results:

• Ionic liquid interactions are primarily driven by hydrophobic components, leading to membrane distortion and vesicle rupture.
• Increased IL concentration progressively decreased the main phase transition temperature of DMPC, indicating enhanced membrane disorder.
• Long hydrophobic cation chains and large hydrophobic anions caused significant membrane rupture, similar to antimicrobial peptides.

Conclusions:

• The study highlights the membrane-disrupting potential of certain ionic liquids, challenging their 'green' reputation.
• Hydrophobicity of both cation and anion significantly influences the extent of IL-induced membrane damage.
• Findings provide insights into the mechanisms of IL toxicity and their potential interactions with biological systems.